Open AccessStereoscopic high-speed imaging of iron microexplosions and nanoparticle-release
Author(s) -
Lihua Shen,
David Sanned,
Jianqing Huang,
Edouard Berrocal,
Weiwei Cai,
Marcus Aldén,
Mattias Richter,
Zhongshan Li
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.434836
Subject(s) - combustion , materials science , shadowgraphy , nanoparticle , particle (ecology) , breakup , optics , particle size , analytical chemistry (journal) , nanotechnology , chemical engineering , chemistry , laser , physics , mechanics , oceanography , organic chemistry , engineering , chromatography , geology
In this work, the combustion behavior of seeded iron particles (d 50 = 70 µm) in a laminar diffusion flame was studied in a modified Mckenna flat-flame burner. Two high speed cameras in stereo configuration allowed 3D position and 3D velocity measurements of burning iron particles as well as 3D evaluation of particle microexplosions. Microexplosive processes are important since it can affect both combustion stability and formation of product components. The observed microexplosions happened before particle extinction resulting in change of trajectories, velocities, radiation intensities and fragmentation into smaller particles. It was observed for the first time that fragments of these microexplosions tend to produce planar structures. A frequent release phenomenon was observed during the iron particle combustion using magnified thermal radiation imaging and high-speed shadowgraphy. This release phenomenon was indirectly confirmed with scanning electron microscopy of combust products, revealing multiple cracked particle shells and hollow structures. Black body radiation characteristics was observed indicating the release being in condensed phase and emission spectroscopy identified FeO as intermediate species during combustion. The observed release is believed to mainly consist of iron-oxide nanoparticles formed in the homogenous reaction between vapor iron and oxidizers.